Well sort of ... when I shut down my HP G72 lappy using either "shutdown -h now" or from the shutdown button in Gnome it shuts down OK. When I plug into AC power and boot it up the following day it shows around 87% charge. If I boot into XP and shut it down the next day the charge shows 100% when I boot up. It looks like linux is not shutting it down properly and something is still using power. I'm using Slackware current but I've tried it with Ubuntu as well and both do the same. Is there any way to diagnose what is going on ?

perhaps its in standby. check the log file in: /var/log/messages

ACPI issue.

http://www.linux.org/docs/ldp/howto/...WTO/index.html

My own experience is the linux OS really cost more energy than the microsoft windows, I have similar test both on my dell inspiron 6000 and hp dv9000 laptop. I tried lots of solutions from linux and ubunto forum, but only help me a little.
You may cut some applications to save more battery life or get a new high capacity extended HP g72 battery, You can also other tips like http://www.battery4us.com/blog/2010/...-battery-life/

@milleygary7

hmm, I remember hearing something about linux being more close to 'realtime OS' than windows (more frequent interrupts or polling or something like that). you can change it somewhere in config files. but responsiveness would probably suffer.
perhaps that is draining battery.